Cell-to-cell communication in bacteria controls a broad range of activities, generally modulated by gene expression, that result in phenotypic changes and adaptation to environmental conditions during growth. The term “quorum sensing”, or “QS” was coined to describe the ability of a population of unicellular bacteria to act as a single multicellular organism in a cell-density-dependent way using small diffusible molecules (see Amara et al., Chem. Rev. 2011, 195-208). There are a number of different classes of “quorum sensing molecules”, QSMs, including oligopeptides, derivatives of dihydroxypentanedione (DPD), N-acyl homoserine lactones (AHLs), and other small molecules.
The signal molecules are produced and secreted during bacterial growth; as the population expands, the concentration of the QSMs increase. Once at a threshold level (e.g. the “quorum level”), these induce phenotypic effects by regulating QS-dependent target gene expression. For example, altered gene expression leads to pigmentation, biofilm formation, and virulence gene expression causing release of proteases, lytic enzymes, and exotoxins.
Quorum quenching (“QQ”) enzymes such as AHL degrading enzymes have been shown to attenuate bacterial infections in fish (see Cao et al., J. App. Environ. Microbio. 78(6):1899 (2012)). These enzymes also have been shown to be useful in control of biofilm fouling of membranes, see Oh et. al., Environ. Science & Tech. 2012, 46:4877-4884 and Lade et al., Int. J. Biol. Sci. 2014 10:550.
The present invention provides novel AHL degrading enzymes and methods for use.